<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        * {
            padding: 0;
            margin: 0;
        }

        html {
            background-color: #F3518A;
            animation: html 4s infinite;
            transition: 1s;
        }
     

        .box3 {
            width: 200px;
            height: 200px;
            background-color: #F3518A;
            margin: 200px auto;
            position: relative;
            transform: rotate(-45deg);
            transition: 1s;
            animation: box3 4s infinite;
        }

        .box3::before {
            content: '';
            width: 200px;
            height: 200px;
            background-color: #F3518A;
            border-radius: 50%;
            position: absolute;
            top: -100px;
            left: 0;
            transition: 1s;
            animation: left 4s infinite;
        }

        .box3::after {
            content: '';
            width: 200px;
            height: 200px;
            background-color: #F3518A;
            border-radius: 50%;
            position: absolute;
            right: -100px;
            bottom: 0;
            transition: 1s; 
            animation: right 4s infinite;
        }


        /* 关键帧 */

        @keyframes html {
            0% {
                background-color: #F3518A;
            }

            50% {
                background-color: #5EAFBA;
            }

            100% {
                background-color: #F3518A;
            }
        }

        @keyframes left {
            0% {
                top: 0;
                background-color: white;
               
            }

            30% {
                top: -100px;
            }

            50% {
                background-color: #F3518A;
            }

            70% {
                top: -100px;
            }

            100% {
                top: 0;
                background-color: white;
             
            }
        }

        @keyframes right {
            0% {
                /* 回到圆形 */
                right: 0;
                background-color: white;
               
            }

            30% {
                
                right: -100px;
            }

            50% {
                background-color: #F3518A;
            }

            70% {
                right: -100px;
            }

            100% {
                right: 0;
                background-color: white;
               
            }
        }

        @keyframes box3 {
            0% {
                /* 白色圆形 */
                transform: rotate(0deg);
                border-radius: 200px;
                background-color: white;
               
            }

            30% {
                transform: rotate(-45deg);
                border-radius: 10px;
            }

            50% {
                background-color: #F3518A;
            }

            70% {
                transform: rotate(-45deg);
                border-radius: 10px;
            }

            100% {
                transform: rotate(-45deg);
                border-radius: 200px;
                background-color: white;
              
            }
        }

     
    </style>
</head>
<body>
   
    <div class="box3"></div>
    

  

</body>
</html>